Add all the dough ingredients, along with the tangzhong to a bowl and either knead by hand or mix on medium low speed on a stand mixer until a smooth elastic dough forms, that can be shaped into a ball. Mine took about 3-4 minutes in the mixer.
Shape the dough into a ball, and transfer to a lightly greased bowl. Cover loosely with a kitchen towel, and let rise in a warm place for about 60-90 minutes until puffy. If you poke the dough, your finger should leave indentations that won't fill back up.
Gently deflate the dough, then divide into 14 equal sized balls, mine were 43 grams each. Pat each dough ball to flatten it out, then place a small square or scoop of cream cheese in the center. Wrap the dough around the cream cheese, and place seam side down in a lightly greased 9 inch circle cake pan or springform pan. Repeat with all the remaining dough balls and cream cheese. Watch the video to see how I arranged them.
Cover again loosely with a kitchen towel and rest again for 40-50 minutes until puffy. Midway through this second rise, you can heat the oven to 350F (180C).
After the doughs are puffy and expanded, brush thoroughly with the egg wash and sprinkle with sesame seeds and nigella seeds. Bake for 25-30 minutes or until deep golden brown on top.
Enjoy warm or room temperature, drizzled with honey. So good!